Unusual Luminescence of Quartz from La Sassa, Tuscany: Insights on the Crystal and Defect Nanostructure of Quartz

Quartz from La Sassa (Tuscany, Italy) presents a unique luminescence related to intrinsic and extrinsic defects in the crystal lattice due to the growth mechanisms in hydrothermal conditions. The bright fluorescence under the UV lamp was apparent to collectors since the early 1970s, and it entered the literature as a reference case of yellow-luminescent quartz. Early reports present the history of the discovery, the geological context, and preliminary luminescence measurements of the quartz nodules, suggesting various activators as potentially responsible of the peculiar luminescence effects: uranyl groups (UO22+), rare earths (Tb3+, Eu3+, Dy3+, Sm3+, Ce3+) and polycyclic aromatic compounds (PAH). Here, we report a full investigation of the La Sassa material, by a multi-analytical approach encompassing cathodoluminescence optical microscopy (OM-CL), laser-induced fluorescence (LIF), wavelength resolved thermally stimulated luminescence (WR-TSL), trace elements analysis by mass spectrometry (ICP-MS) and Raman spectroscopy (RS). The results provide a significant step forward in the interpretation of the luminescence mechanisms: the main luminescent centres are identified as alkali-compensated (mainly Li+ and Na+, K+ and H+) aluminum [AlO4/M+]0 centres substituting for Si, where the recombination of a self-trapped exciton (STE) or an electron at a nonbridging oxygen hole centre (NBOHC) are active.

Supplemental Material: The Middle-Late Cretaceous Zagros ophiolites, Iran: Linking of a 3000 km swath of subduction initiation fore-arc lithosphere from Troodos, Cyprus to Oman

Table S1: Zircon O and Lu-Hf isotopic composition of the Zagros inner-belt and outer-belt ophiolitic rocks; Table S2: Whole rock major and trace elements analysis of the Zagros inner-belt and outer-belt ophiolitic rocks; Table S3: LA-ICP-MS U-Pb analyses of zircons from the Zagros inner-belt and outer-belt ophiolites; Table S4: SIMS U-Pb analyses of zircon from the Zagros inner-belt and outer-belt ophiolites; Appendix A.

Supplemental Material: The Middle-Late Cretaceous Zagros ophiolites, Iran: Linking of a 3000 km swath of subduction initiation fore-arc lithosphere from Troodos, Cyprus to Oman

Table S1: Zircon O and Lu-Hf isotopic composition of the Zagros inner-belt and outer-belt ophiolitic rocks; Table S2: Whole rock major and trace elements analysis of the Zagros inner-belt and outer-belt ophiolitic rocks; Table S3: LA-ICP-MS U-Pb analyses of zircons from the Zagros inner-belt and outer-belt ophiolites; Table S4: SIMS U-Pb analyses of zircon from the Zagros inner-belt and outer-belt ophiolites; Appendix A.

PETROGENESIS, MAJOR OXIDES AND TRACE ELEMENTS GEOCHEMISTRY OF MIGMATITE IN AJUBA, KWARA STATE, NIGERIA

Petrogenesis, major oxides and trace elements geochemical study was carried out on migmatite in Ajuba. The study area is located on Latitudes 8° 05'N and 8°13'N and Longitudes 5°23'E and 5°30'E. Five rock samples were taken from the migmatite outcrops and used for petrographic and geochemical analyses. The geochemical analysis was done using X-ray Fluorescence Spectrometer technique. The dominant rock type is migmatite; gneiss and granite outcrops were also found in sparse distribution. Ptygmatic folds, which constitute the palaeosome, is the common structure observed on the migmatite rock. The petrographic analysis shows that the migmatite consists of quartz, biotite, plagioclase, hornblende and microcline. The major oxides analysis indicates SiO2 as the dominant oxide with concentration range values (70.71 wt. % - 79.32 wt. %) and average of 74.80 wt. %. Al2O3 (14.98 wt. % - 16.44 wt. %, average: 15.70 wt. %) and Fe2O3 (9.10 wt. % - 15.41 wt. %, average: 12.39 wt. %), K2O (6.67 wt. % - 8.86 wt. %, average: 7.50 wt. %) and CaO (0.49 Wt. % - 4.64 wt. %. average: 2.73 wt. %). P2O5, MnO and TiO2 are less than 1.0 wt. %. The trace elements analysis indicates the concentration distributions: Rb (0.11-0.15 ppm, average 0.13 ppm), Co (0.04-0.17 ppm, average 0.10 ppm). Trace elements ˂ 0.10 ppm are Zn, W, Ni, Cu, V and Pb. From the petrographic and geochemical assessment, the petrogenesis of the migmatite has silica-rich igneous parentage. Moreover, the plots of SiO2-CaO and K2O-SiO2 placed the migmatite on the “upper boundary field of Francisian Greywacke” protolith and Shoshonite series, respectively.

Geochemical analysis for evaluating the paleoweathering, paleoclimate, and depositional environments of the siliciclastic Miocene-Pliocene sequence at Al-Rehaili area, Northern Jeddah, Saudi Arabia

Geochemical data and their various approaches are useful to evaluate the climatic control on the depositional environments. This study aims to evaluate the paleoweathering and plaeoclimate condition that have controls on the depositional environments of the Miocene to Pliocene siliciclastic sequence at Al-Rehaili area, north of Jeddah. To achieve this aim, selected sandstone samples were geochemically (major and trace elements analysis) and petrographically examined. The results of these analyses reveal that the examined sandstones were deposited in non-marine (fluvial/alluvial-lacustrine) environments and suffered from weak to intermediate chemical weathering and intense physical induration under semi-arid to semi-humid climatic conditions.

Paleogeographic framework and Paleo-sedimentary environmental restoration in the Lower Part of Yanchang formation in Triassic of Ordos Basin, China

<p><strong>Title: Paleogeographic framework and Paleo-sedimentary environmental restoration in the Lower Part of Yanchang formation in Triassic of Ordos Basin, Chin</strong><strong>a</strong></p><p>Ordos basin is a craton basin, rich in coal, oil and natural gas resources. The Yanchang formation includes the lower part (Chang 10- Chang 8 oil bearing intervals) and the upper part (Chang 7- Chang 1 oil bearing intervals) in which we found many hydrocarbon-rich depressions. The sedimentary period of Chang 10-Chang 8 formation is the transition stage from the North China Craton depression basin to  Ordos basin due to the influence of the Indosinian movement. Previous studies mainly focused on the the interior of the present residual basin rather than the peripheral of the basin.</p><p>Twenty five outcrops out of Ordos basin and one hundred drilling cores in the basin are used and multiple methods including microscope, SEM observation , the major-trace elements analysis ; zircon U-Pb geochronological studies and seismic profile interpretation are applied to study the paleoredox, paleosalinity , paleoclimate and provenance of the the lower part of the Yanchang formation in the Ordos basin.</p><p>It is concluded that: (1)the main charateristics of the sedimentary facies about Chang 10 is rivers-deltas- shore-shallow lacustrine. The sedimentary facies of Chang 9 has the features of “multi-deltas surrounding the lake” with a transitory lake transgression. The main charateristics of Chang 8 is that the rivers became more powerful and the area of lake increased.(2) based on the zircon U-Pb age structure comparision beween the lower part the Yanchang formation and its periphery old land, the results indicate that it has consistent source, which are mainly northern and southern margin of Huabei block. However, the north-east Alashan old land and south Qinlin-Qilian tectonic belts may just supply few detrital sediments.(3) according to the seismic interpretation, we have found a large number of synsedimentary fault. Seismites developed in Chang9 and Chang8 and turbidite developed in Chang9. The distribution of the synsedimentary fault, seismites and turbidite can cetify that the structure activity was more active in the sedimentary period of the Yanchang formation.</p>